236 0F CONVEYING BOATS OR BARGES ON CANALS. 



continue the fame. Obje&s of a nature fo unlike, are in- 

 capable of union. On the other hand, the will of man con- 

 tinues unimpaired ; it is this which muft counterbalance the 

 operation of the organs, morality ought to fubdue the paf- 

 fions." 



BOJAMES, M. D. 



VII. 



Method of conveying Boats or Barges from a higher to a lower 

 Level, and the contrary, on Canals, by means of a Plunger, 

 injiead of lofmg Water by Locks. By Law son Huddle- 

 ston, Efq. of Shaftfbury, Dorjlt. Communicated by the In-* 

 ventor. 



Conftru&ion of WHEREVER there is occafion to convey a commercial 



a lock for railing b oat or Dar cr e from a higher canal to a lower (ufually termed 



and lowering ~ ° * J 



boats. a higher or lower line) or vice verfa, a lock mufl be conftructed 



of ftone or other fit materials in the fpace between the higher 

 and lower canal, fo as to communicate at the ends with both 

 of them. The dimeniions of the lock are to be as follow ; its 

 horizontal fuperficies or area fliould correfpond both in form 

 and tize with that of the boat itfelf, with the allowance of 

 fufficient room only for the boat to rife and fink freely within 

 it ; and its depth and height ihould be fuch that the water 

 within it may rife with a loaded boat floating therein from the 

 level of the lower to that of the higher canal : there muft alfo 

 be two fluices one at each end of the lock, large enough to 

 admit the free ingrefs and egrefs of the boat, one of which 

 muft be accommodated to the level of the higher canal, the 

 other to that of the lower. 

 Refervoiron one On one fide of the lock there muft be a refervoir of equal 

 fide of the lock, height with that of the lock, the form of which may be rectan- 

 gular or not (though the former may perhaps be the more con- 

 venient) the area of which fliould be equal to, or rather in 

 practice fomewhat exceeding, that of the lock. In this cafe 

 the perpendicular depth of the refervoir fliould be equal to 

 double the intended rife or fall of the vetfel within the lock, 

 but where the areas of the lock and refervoir are unequal this 

 proportion varies: for as in all cafes the quantity of water to 



4 be 





